1、Installation Instructions3-Vane and 4-vane Secondary MountsRev 6/09List of Parts Included With Each KitITEM DESCRIPTION1 Spider2 Collimating adjustment screws, 3 pcs.3 Tensioning nut4 Clutch disk5 Mirror holder body6 Mirror pad7 Secondary mirror (not included - available separately)8 Mirror shroud (
2、not included on 0.75” and 1.00” models)9 Shroud mounting screws10 Nylon mirror spacers, 3 pcs (not shown)11 Drill bit (not shown)12 Collimation adjustment tool (not shown)13 Spider mounting screws, quantity varies (not shown)23 591476 8Photo courtesy of Kevin Collins1Install the Mirror Into the Hold
3、erThe secondary mirror can be installed in the holder by two differentmethods; shroud mounting or adhesive mounting. (Note: 0.75” and 1.00”models only use the adhesive mounting method.) The metal shroud can beused (Method #1 below) when the mirror is the same size as the holderbody (e.g., a 2.14” mi
4、rror in a 2.14” holder). For non-standard or oversizedmirrors, the mirror should be glued to the face of the holder asdescribed in Method #2 below.Method #1: Using the metal shroudRemove the screws holding the metal shroud,and remove the shroud. Place the mirror on the holderface with the foam pad u
5、nder the mirror. Slip theshroud over the mirror and holder, and loosely installthe side retaining screws. Position the shroud ontothe mirror until the tabs lightly contact the mirrorsurface. Do not push the shroud too tightly againstthe mirror, or you may deform the optical surface ordamage the opti
6、cal coatings. Snug tighten the shroudretaining screws.Important Note: Secondary mirrors made from glass castings vary in size.If your secondary mirror does not seat properly in the mirror shroud, it isprobably slightly larger than the advertised size. In this case, mount themirror with the adhesive
7、method (Method #2 below). Mounting an oversizedmirror in the shroud can result in unacceptable surface deformation, or“pinched optics”. (ProtoStar secondary mirrors are CNC machined to sizeto ensure a proper fit.Method #2: Adhesive attachmentIf you are using an oversized or non-standard size seconda
8、ry mirror, you canglue it to the face of the mirror holder.Use a silicone-based adhesive only, anduse a fresh tube (there is a catalyticcomponent that evaporates with time).Make sure both the mirror back anddiagonal head are clean and free of oilsprior to applying the adhesive.First, glue the suppli
9、ed plasticspacers to the face of the diagonal headINSTALLATIONFigure 1: Shroud-mountedsecondary mirror2Figure 2: Commonsilicone adhesivesas shown in photos above. Leave the spacers in place, and glue thesecondary mirror on with several small dollops of adhesive. Let the adhesivecure for 24 hours at
10、room temperature.It is a good idea to cover the exposed edge of the secondary mirror tosuppress stray light. You can make a wrap-around shield that conforms tothe edge of the mirror, and either paint it flat black paint, or cover it with ascrap of flocked light trap material.Install the SpiderMeasur
11、e the overhang dimensionBefore drilling spider mounting holes, determine what the overhangdimension is for your assembled secondary mount. The overhang is thedistance from the spider mounting holes to the center of the secondarymirror (which is also the focusers axis), and is shown as dimension A in
12、Figure 4. Its not necessary to measure with high precision because thesecondarys position can be later fine-tuned within a range of adjustment.To make this measurement, turn the three collimation screws in thespiders hub until they protrude about 1/8” (3 mm) out the back of the hub.Next, install the
13、 mirror holder (with mirror installed) into the spider until thecollimation screws seat into the dimples of the clutch disk. Install and fingertighten the main tensioning nut by hand. Measure the overhang by eyedirectly along the midline of the secondary using a ruler or tape measure.Mounting the sp
14、iderIt is generally easier to combine the spider and holder outside thetelescope before installing into the tube. This permits a visual inspection toensure the collimation screws are engaged into the clutch dimples, and theanti-dew connecting wire (if equipped) is stowed properly.Siliconeadhesivedol
15、lupsPlastic spacers(supplied)Spacers create thin gapwhich prevents opticalmounting strainFigure 3: Gluing the mirror to the holder with spacers34Figure 4: Spider overhang dimensionDrill the spider mounting holes in your tube or upper cage using thesupplied drill bit. For solid tube telescopes, a wra
16、p-around paper templateis useful for making sure the holes are accurately located. Install the spiderwith the supplied #8-32 screws (M5-0.8 for metric spiders). Start the screwswith your fingers only. The stainless steel screws are much harder thanthe soft aluminum vane lugs, and its easy to cross-t
17、hread the screws. Fingerturning allows you to feel the screw threads engaging properly. Finishtightening with a screwdriver. Do not overtighten the vane screws, ashighly tensioned vanes are not required to achieve collimation stability.Note: Protostar spiders are normally sized so that there is a sm
18、all gapbetween the tip of each vane and the tubes inside wall. This gap permitsprecise centering adjustments, and ensures the vanes will always remain isslight tension.USE and MAINTENANCEHow it worksUnlike traditional ball and socket pivot designs, Protostar secondarymounts use a semi-rigid shaft wh
19、ich permits the range of secondary mirrortilt required. Three collimating screws press against a clutch disk on theback of the mirror holder. The clutch restricts the action of the collimatingscrews to tilt adjustment only, and prevents the mirror holder rotation whileyou turn the collimation screws
20、. It is important that the collimation screwsare seated in the recessed dimples on the clutch disk. There are smallnotches on the outside of the clutch disk to permit a visual check that thecollimation screws are aligned with the dimples.A major benefit of the design is that it simplifies collimatio
21、n of thesecondary mirror. The tilt adjustment of the secondary mirror can be donedirectly, without the need to unlock a nut first. Similarly, nothing needs to be“locked down” to hold collimation in place. The system tension (see below)is relied upon to hold all adjustments in place. In addition, the
22、 design permitsmost collimating screw adjustments to be made independently (i.e., youcan tighten one without having to also loosen others).System tensionThe schematic below shows how system tension is created. Tension isdeveloped in the semi-rigid stem by tightening the tensioning nut, whichcauses a
23、 reactive compressive force between the clutch disk and diagonalhead. In order for the diagonal mount to maintain collimation, there needsto be enough system tension to prevent the clutch from slipping. This canusually be achieved by hand tightening the tensioning nut. A good way tocheck for suffici
24、ent system tension is by trying to rotate the diagonal head.It should turn by hand, but with considerable frictional drag.5TENSIONING NUTSEMI-RIGID SHAFTTension inthis membercauses. clutchfriction here.Figure 5: How it worksCLUTCH DISKCLUTCH DIMPLES6Collimation tipsProtostar secondary mounts work a
25、bit differently than most othercommercial secondary mounts. Here are a few important tips to remember: It is usually easier to marry the secondary holder and spider togetheroutside the telescope, and install as one unit. This is especially true for unitswith the built-in dew heater. For precise axia
26、l positioning of the secondary mirror under the focuser,move the holder to/from the primary mirror by alternately adjusting thecollimation screws and tensioning nut.To move the secondary closer to the primary mirror, first loosen(counterclockwise) the tensioning nut a half turn, and then tighten (cl
27、ockwise)the three collimation screws until you feel resistance (make sure they remainaligned with the clutch dimples). Repeat as necessary.To move the secondary away from the primary mirror, first loosen(counterclockwise) the three collimation screws by about one turn each,and then finger tighten (c
28、lockwise) the tension nut until it is snug. Repeat asnecessary.Positioning the secondary axially may take several repetitions, but keepin mind you only need to do this for the very first collimation. Subsequentcollimation will go much faster. Start the collimation process with the tensioning nut onl
29、y finger tight.If most of your subsequent turns of the collimation screws are clockwise,this us usually enough to tighten and lock the system in place with no furtheraction. If you find the secondary holder is still too loose, you can manuallytighten the tensioning nut another half turn. Do not tigh
30、ten the tensioningnut more than is needed to just keep the holder from rotating freely. Thesecondary mount is designed to hold collimation with very little friction andtension in the system. After completing collimation with the tool of your choice (Cheshire,laser, etc.), just take you hands off. Yo
31、ure done! It is not necessary to tightenanything else.Service and replacement partsProtostar secondary mounts can be returned for a factory refurbishmentand refinish for a modest fee (see our website for details). Most of the majorcomponents can also be purchased as replacement parts. 1996-2009 ProtostarP.O. Box 448Worthington, Ohio 43085U.S.A.technical support: (614)-785-0245e-mail: protostarfpi-www.fpi-
